Interview with Jennifer Harkless from Spectrum Control

  • Jennifer Harkless - Product Line Manager

EMC Directory recently interviewed Jennifer Harkless who is Product Line Manager at Spectrum Control. Spectrum Control (formerly APITech) is a world leader in technologies, components, and subsystems to manage and control the electromagnetic spectrum. Jennifer is an experienced Operational Excellence Manager with a demonstrated history of working in the consumer goods industry.

Q. Can you give us a brief overview of Spectrum Control?

Jennifer: Spectrum Control has been the world's leading provider of EMI filter solutions since 1968. Our design process begins with an extensive library of standard components that our experienced team frequently develops into custom assemblies, allowing us to offer a complete, high-performance solution. Customers rely on us to provide rugged, reliable, and efficient assemblies and components for use in the most mission-critical defense and military applications, supporting government programs throughout the world.

Q. Can you tell us more about your EMI protection products?

Jennifer: Our team takes great pride in the fact that Spectrum Control has an industry-leading EMI filter product line that has over 800 standard QPL products and DSCC part numbers. Our portfolio includes glass and resin seal filters, surface mount filters, filter plates and arrays, filtered connectors, and military/aerospace power line filters, most of which are RoHS compliant.  

Q. What are the common sources and propagation paths of EMI, and how can they be effectively controlled or eliminated in Electronic Systems?

Jennifer: EMI can be at a single frequency or across a broad range of frequencies. EMI encompasses the entire electromagnetic spectrum but is most applicable to modern electronic devices over the frequency range of 10 kHz to 10 GHz.

Unintentional EMI sources include switch-mode power supplies (SMPS), digital devices, brushed DC motors, high-voltage ignition systems, and fluorescent lighting. Intentional EMI sources are most commonly radio frequency (RF) transmitters, whose emissions are often referred to as Radio Frequency Interference (RFI). AM radio, FM radio, television, cell phones, Wi-Fi, Bluetooth, and many other fixed and mobile radio communication systems used by aviation, emergency services, police, and the military are the typical causes of RFI.

Intermittent EMI are transients that can cause catastrophic damage to electronics. Examples include electrostatic discharge, lightning, inductive kickback, and electromagnetic pulse events (EMP).

EMI filters ensure multiple electronic devices can function acceptably within the same electromagnetic environment but not interfere with each other in operation.

Q. Spectrum Control also develops application-specific EMI filtered Connector Solutions. Can you tell us more about these products? Where are these products used?

Jennifer: Because our engineers have extensive experience and many have worked together for decades, we have been able to develop the industry’s most extensive line of interconnect products. Our customers use our products in high-reliability and demanding environmental applications, such as commercial aviation and avionics, highway, and agricultural vehicles, high-reliability power supplies, as well as all airborne, ship, or ground-based military applications.

Our filtered interconnect offerings are vertically integrated. We build components, including ceramic capacitors, in-house, so customers receive high-quality parts in the industry’s shortest lead times.

Some of our products are filtered circular and d-sub connectors, filter assemblies, and hot shoe-style connectors. We also design a filtered connector specifically for power lines with integrated common and differential mode EMI filtering.

Q. Can you tell us more about the Custom Circular Connectors for EMI protection that you offer? What is the advantage of circular connectors? What type of customizations do you support? What is the lead time for these custom solutions?

Jennifer: It’s important to listen to customers and their applications, as each product has to meet the specific requirements of how it will be used. Taking this approach allows us to offer custom circular connectors in EMI-filtered styles, including military standards, based on particular needs. One example is our EMI filter compact shell connectors, which provide an effective filtering device that reduces the amount of real estate required within a product enclosure. Using our expertise in EMI filter design and manufacturing, we offer planar-style filter arrays, available in C and Pi circuits up to 200nF in most configurations. Other filter circuits, including transient protection, are available.

As mentioned, we build ceramic capacitors for our connectors in-house, so our lead time can be as low as 14 to 16 weeks for our filtered circular connectors.

Custom Circular EMI Filtered Connectors

Q. Can you tell us about your 5G EMI-filtered D-sub connectors? What are these and where are they used?

Jennifer:  Radio communication testing platforms, such as RF test enclosures, are designed for both signaling and nonsignaling testing. This includes shielding cubes for high-frequency testing of 5G cellular devices. One benefit of our platform is that we build filtered d-sub connectors with capacitors that strip unwanted noise or EMI that can impact test equipment system performance (up to 6 GHz and beyond).

Our 5G d-sub connectors are built with a multi-pole circuit that utilizes materials specifically designed for 5G cellular bands. This market-leading coaxial construction offers a soldered lead to the capacitor and capacitor to its die-cast shell, making it ideal for high-frequency 5G testing.

5G EMI Filter D-Sub Connectors

Q. Tell us more about your in-house EMC lab and what capabilities you have for your customers.

Jennifer: Our in-house, fully equipped EMC laboratory offers customers a flexible resource to assist product development by identifying and correcting EMI susceptibility and emission problems. Spectrum Control engineers evaluate and fine-tune installed filter performance to find a solution for your design requirements.

Spectrum Control takes great pride in having an experienced engineering staff that solves the most demanding EMC challenges that other companies cannot. We can test a customer’s equipment, determine the state of compliance, and develop a viable solution. It is not uncommon for our clients to leave our lab with an EMI solution prototype in hand.

Q. How can customers buy your products? Do you sell directly or work with distributors? Please tell us more about your sales channels.

Jennifer: Spectrum Control, Inc. offers customers the easiest path to source EMI filters.  We have a large authorized distribution network and sales channels readily available. Please see resource page for all the available sales resources. 

Q. Who are your customers and what market segments do you cater to and which is the largest segment for you?

Jennifer: Spectrum Control products are used by global defense, industrial, and commercial customers in applications spanning radar, electronic warfare, unmanned systems, missile defense, harsh environments communications, medical, instrumentation, and many more. We recently developed products for space-grade applications, including satellites, ground transmission, launch vehicles, and communication networks.

Our customer base is broad because all electronics are susceptible to interference. Every system is unique, which is where our experience can become very advantageous. Spectrum Control has the proficiency to solve not only common interference issues but also unexpected EMI problems that will arise.

About Spectrum Control

Spectrum Control (formerly APITech) stands as a global leader in technologies, components, and subsystems dedicated to managing and controlling the electromagnetic spectrum. Innovators worldwide consistently turn to Spectrum Control, relying on its leading engineering and design teams and incorporating its proven solutions into their projects. The ongoing commitment to investing in top-tier engineering talent empowers Spectrum Control to conceive and deliver high-performance solutions within compact footprints, capable of operating in the most challenging conditions. The company continually pushes the boundaries of what is achievable through the integration of new disruptive technologies.

The product portfolio at Spectrum Control primarily revolves around signal conditioning, processing, distribution, and protection. The company provides a comprehensive range of RF, microwave, millimeter wave, and optical solutions, featuring renowned brands such as Inmet and Weinschel products. Additionally, the company offers EMI protection products that are meticulously designed and manufactured by the original Spectrum Control and Spectrum Microwave teams. Spectrum Control's clientele consists of industry leaders in Aerospace & Defense, as well as commercial applications.

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